What about a VESA framebuffer? AFAIK, nearly every graphics card in
the
market support VESA 1.x (at least). During installation, Anaconda could
check if the videocard supports VESA and, if so, install rhgb.
If you trigger VESA mode you can't then use some X servers and the VESA
mode switch is 16bit only so its very hard to get back out of it